The invention relates to a wastewater pumping station, having at least one solids collecting tank for wastewater which is guided through the same and is loaded with solids, additionally having a liquid collecting tank for the wastewater which has been rid of solids and has been pretreated in the solids collecting tank and having a wastewater shaft for receiving at least the solids collecting tank and the liquid collecting tank, wherein the liquid collecting tank and the wastewater shaft comprise at least one common wall surface.
As is known, wastewater pumping stations are typically utilized for the purpose of pumping wastewater, which has collected at the bottom of a wastewater storage chamber, up to a certain level. After this, further treatment is then effected in the majority of cases in a wastewater treatment plant. In the past and in the prior art, the wastewater is frequently pumped using large, inefficient pumps.
For this reason, the generic teaching according to European patent document no. EP 1 108 822 A1 describes a wastewater pumping station where raw solids or solids are separated from the conveying medium, as a rule the wastewater, before said wastewater enters into a pump that is used. A solids collecting tank which is connected upstream of the pump takes care of the described separation. The solids are ideally held back in the solids collecting tank such that wastewater that has been pretreated once is transferred into a liquid collecting tank which is connected downstream of the solids collecting tank.
The wastewater pumping stations used in practice are typically received and placed in a wastewater shaft which is produced from concrete. The possibility of the liquid collecting tank and the wastewater shaft which receives the wastewater pumping station being produced from plastics material is described over and above this within the framework of generic European patent document no. EP 1 108 822 A1. In this case, the shaft bottom simultaneously forms the bottom of the liquid collecting tank.
German patent document no. DE 295 05 028 U1, which is also generic, proceeds in a similar manner. In this case, a center wall in the wastewater shaft and part of the shaft wall form the liquid collecting tank. The shaft wall and the center wall or all remaining walls are produced from plastics material in the sense of a structural bond. Costs and installation space are to be saved as a result.
The known measures are not without problems. For a wastewater shaft which is produced, for example, from concrete has first of all to be established and constructed on site. As a rule, the wastewater pumping station is then installed after that. In this case, a liquid collecting tank, which is produced from metal or plastics material, is chosen in practice for the most part. Said liquid collecting tank is designed in a separate and independent manner from the wastewater shaft and is received in the wastewater shaft in question.
In the case of the teaching according to European patent document no. EP 1 108 822 A1, the liquid collecting tank and the wastewater shaft are produced from plastics material, the shaft bottom simultaneously forming the bottom of the liquid collecting tank. As a result, the installation site of the liquid collecting tank in the wastewater shaft is restricted. In addition, there is no longer additional installation space available on the bottom. More significant, however, is the choice of material (plastics material). Wastewater shafts produced from plastics material are certainly able to be industrially prefabricated and cost advantages result from this (cf. German patent document no. DE 295 05 028 U1). However, these types of structures frequently cannot always cope or cannot always cope in the long term with the static and dynamic loads at the installation site. The invention aims to create a remedy here overall.
The technical problem underlying the invention is to develop further a wastewater pumping station of this type such that long-term operation is ensured and at the same time cost advantages during production are seen.
To solve said technical problem, a generic wastewater pumping station within the framework of the invention is characterized in that the liquid collecting tank defines a closed chamber in the wastewater shaft with an only partially covered bottom area and to this end is provided with at least one wall surface which is independent of the wastewater shaft and is of different material.
In the first instance, a liquid collecting tank, which defines a closed chamber in the wastewater shaft, is realized within the framework of the invention, that is to say has a bottom, side walls and a head-end cover. As the liquid collecting tank in question only covers the floor area in the wastewater shaft or of the wastewater shaft in a partial manner, there is an installation area or a space for structures available on the floor area of the wastewater shaft which is not taken up by the liquid collecting tank.
Said installation area or space can be utilized, for example, for mounting one or several pumps at that location. The relevant pump, in this case, is assigned to the solids collecting tank and serves for emptying the liquid collecting tank via the solids collecting tank in question. At any rate, the pump in question (where applicable in connection with further elements of the wastewater pumping station) is able to be mounted and placed dry in the space already addressed which is available in the wastewater shaft because the liquid collecting tank only covers part of the floor area of the wastewater shaft.
Not only the installation of the one or the several pumps is facilitated in this way, but maintenance of the pump is also able to be realized and implemented during operation. In the same way, the available installation area or space can also be utilized for mounting and placing a distributor casing or a distributor which guides and conducts the wastewater, which is loaded with the solids, to the solids collecting tank. Coarse solids can be separated from the wastewater in the distributor casing.
In any case, it is possible within the framework of the invention to accommodate the distributor casing in the space addressed such that the installation and the maintenance as well as the accessibility are facilitated. The same applies to the solids collecting tank. In said context, it ought to be stressed that the space is realized not only next to the liquid collecting tank on the bottom surface of the wastewater shaft that is not covered by the liquid collecting tank, but the space can also extend further in the wastewater shaft above the head-end cover of the liquid collecting tank. A particularly compact design and in particular a reduced shaft diameter is seen as a result.
In said context, the invention provides that the head-end cover in question is designed so as to be removable where applicable. As a result, possible maintenance work is made even easier. By designing the cover or the wall surface that is independent of the wastewater shaft in different materials compared to the wastewater shaft, it is possible to design the wastewater shaft in a dense manner from, for example, concrete, whereas the wall surfaces of the liquid collecting tank which are independent of the wastewater shaft can be produced typically from plastics material or metal. Said mixture of materials combines significant stability of the wastewater shaft and of the liquid collecting tank with particular cost advantages.
Apart from this, the liquid collecting tank can be provided with an inspection opening which can be removed or rather opened for maintenance purposes or also for checking the liquid collecting tank. The liquid collecting tank can be checked and also cleaned in this way where necessary.
Over and above this, the liquid collecting tank may be realized in a tight manner, and in particular in a gas-tight manner, in order to hold back possible foul gases which may be generated. So that an overpressure is not generated in this context in the liquid collecting tank, liquid collecting tank may be provided with a vent.
Should an overflow of the liquid collecting tank or of the wastewater shaft as a whole nevertheless ever be observed, an additional sump pump ensures that the wastewater shaft is able to be emptied by the same. Said sump pump is regularly placed in the already addressed space or installation area on the bottom surface of the wastewater shaft which is not covered by the liquid collecting tank.
Over and above this, the liquid collecting tank may be provided with at least one oblique surface for reducing deposits. Effectively, suspended matter, which can result in deposits in the interior of the liquid collecting tank, is still situated in the pretreated wastewater which is trapped and collected in the liquid collecting tank. Within the framework of the invention, said suspended matter is now guided along the oblique surface for reducing deposits as far as to the lowest point in the tank, from where it can be sucked up by the pump. In this case, said lowest point in the tank typically coincides with a suction region covered by the pump such that possible deposits can be conveyed directly into the pump intake, sucked in here by the pump and ultimately removed via the solids collecting tank. As a result, possible maintenance and cleaning work on the liquid collecting tank can be reduced to a minimum.
The design according to the invention of the liquid collecting tank as a closed space, with the bottom surface in the wastewater shaft only partially covered, provides over and above this the possibility of arranging the solids collecting tank as well as the optional pump and, where applicable, the distributor or the distributor casing (in each case) inside, partially inside or even outside the liquid collecting tank in the wastewater shaft. As a rule and for reasons of simple maintenance, the aforementioned components are typically placed outside the liquid collecting tank in order to keep them easily accessible. In principle, however, it is also possible to incorporate individual or all of the aforementioned components in part or also completely into the liquid collecting tank in order to implement a particularly compact design.
However, such a compact design is already made available according to the invention as a result of the basic structure because the liquid collecting tank and the wastewater shaft comprise at least one common wall surface. Said common wall surface can be a side wall surface and/or a bottom surface. In contrast, a common cover surface for the liquid collecting tank and the wastewater shaft is regularly not realized, although it is not excluded either within the framework of the invention.
In order to be able to implement this in detail, the common wall surface of the liquid collecting tank and of the wastewater shaft are realized according to an advantageous development of uniform material. That is to say, in this case the liquid collecting tank utilizes the common wall surface with the wastewater shaft and does not have its own wall in said region. Particular cost advantages are obtained as a result because the wall in question of the liquid collecting tank is unnecessary and consequently needs neither to be produced nor constructed.
As an alternative to this or in addition to it, the common wall surface of the liquid collecting tank and of the wastewater shaft can also consist of two materials which are joined together. In said case, the wall of the liquid collecting tank, on the one hand, and the wall of the wastewater shaft, on the other hand, are designed in each case so as to be independent of one another, but joined together. As a result, for example, the wall of the wastewater shaft can be additionally utilized to support the wall of the liquid collecting tank and to stabilize the same.
Finally, as a further alternative to this or also in addition to it within the framework of the invention, there is the option in the space for the common wall surface of the liquid collecting tank and that of the wastewater shaft to function as a lost mold. That is to say, in this case the wall of the liquid collecting tank, which at the same time provides the wall of the wastewater shaft, is typically utilized as a mold in the production of the liquid collecting tank or the corresponding wall is left out. For example, the liquid collecting tank may be a plastics material tank which is produced in an injection molding mold. The common wall surface with the wastewater shaft functions in this case as a lost mold. The said common wall surface therefore does not necessarily need to be taken into consideration in production.
Finally, it is recommended when the liquid collecting tank and the wastewater shaft are produced from concrete, metal, plastics material as well as combinations. In this case, in the region of the wall surface of the liquid collecting tank which is independent of the wastewater shaft, in each case a material that is different from the wastewater shaft is used. In the simplest case, the liquid collecting tank can be implemented and realized in such a manner in the interior of the wastewater shaft (produced from concrete) that an additional wall (produced from concrete) is drawn-into the wastewater shaft and is closed by way of a head-end cover which is produced, for example, from plastics material or metal. At any rate, the wastewater pumping station according to the invention is designed in a particularly compact and cost-efficient manner and provides advantages for maintenance and cleaning. These are the essential advantages.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.